You will need 6 to 8 ounces of bulky yarn. Look for the ones with a number 5 or 6 on the label. A size N crochet hook.
Start with a fsc of 90 (this is my favorite link for explaining how to do the foundationn single chain), chain one, turn.
Row 2 work 2 half double crochets in each stitch across. Chain one, turn. (180 hdc)
Row 3 work 2 half double crochets in each stitch across. Chain one, turn. (360 hdc)
Row 4 work 2 half double crochets in each stitch across. Fasten off and weave in loose ends. (720 hdc)
Depending upon the yarn use, and how tight or loose your stitches are this will measure approximately 2.75 inches to 3.25 inches across, and 56 inches and 62 inches long. The increases in each stitch across helps it to spiral, and gives it a ruffled look when worn.
The scarf pictured was made with a nylon/acrylic blend boucle type yarn.